If someone were to lend me a time machine and ask me to go back and figure out exactly what first set me down my road to dedicated descriptivism, I would first ask them if perhaps there wasn’t a better use for this marvelous contraption. But if they persisted, the coordinates I’d start with would be my elementary school days. I suspect it was some time around then that I first asked for permission to do something and was met with one of the archetypal prescriptions.

“Can I go to the bathroom?”, I surely must have asked, and just as surely a teacher must have answered, “I don’t know, can you?”

The irritation that I felt at this correction was so severe that even though I can’t remember when this happened, nor who did it to me, I still can call to mind the way it made me seethe. It was clear to me that the pedant was wrong, but I couldn’t figure out quite how to explain it. So, at the risk of sounding like I’m trying to settle a two-decade-old grudge, let’s look at whether it makes sense to correct this. I say that the answer is no — or at the very least, that one oughtn’t to correct it so snootily.

Let’s examine the “error” that the authority figure is correcting. Can, we are told, addresses the ability to do something, whereas may addresses permission. Mom said I can count to ten means that dear ol’ Mum believes in my ability to count to ten, although she may not want me to do so; Mom said I may count to ten means that Mum is allowing me to do so, although she need not believe that I am able to.*

At any given time, there are a lot of things that one is capable of doing (can do) and a lot of things that one is permitted to do (may do), and a few things that fall into both categories. The prescriptivist idea is that there is a fairly clear distinction between the two categories, though, and so it is important to distinguish them.

Except, well, it’s not so important after all; can and may were tightly intertwined in early English, and were never fully separated. The OED lists an obsolete usage [II.4a] of may as meaning “be able; can”. This is first attested in Old English, and continues through to at least 1645. Furthermore, may meaning “expressing objective possibility” [II.5] is attested from Old English to the present day (although it is noted as being rare now). Examples of these are given in (1) and (2). So we see that may does not always address the issue of permission, that may has encroached upon can‘s territory at times in the past and continues to do so to this day.

(1) No man may separate me from thee. [1582]
(2) Youth clubs may be found in all districts of the city. [1940]

As for can, there’s no historical evidence I found of it referring to permission in the distant past. Back then, may was apparently the dominant one, stealing usages from can. The OED gives a first citation for can meaning “to be allowed to” in 1879, by Alfred, Lord Tennyson, and does call the usage colloquial, at least on the British side of the pond. But still, we’ve got it attested 130 years ago by a former Poet Laureate of the UK. That’s a pretty good lineage for the permission usage.

Furthermore, I think (at least in contemporary American English) that the may I usage is old-fashioned to the point of sounding stilted or even affected outside of highly formal contexts. Just to back up my intuition, here’s the Google Books N-grams chart comparing May I go and Can I go:

You can see there’s a changeover in the mid-1960s, when the usage levels of May I finish plunging and Can I starts rocketing away. As you well know, this sort of fairly sudden change in relative frequency tends to generate a backlash against the newly-prominent form as a sign of linguistic apocalypse, so there’s no real surprise that people would loudly oppose permissive Can I. As always, the loud opposition to it is one of the surest signs that it’s passed a point of no return. By my youth, Can I was ensconced as the question of choice, and nowadays, I doubt many of our kids are getting being corrected on it — though it remains prominent enough in our zeitgeist to function as a set-up for a range of uninspired jokes.

So historically, what can we say of can and may and permission and ability? We’ve seen something of a historical switch. In the distant past, may could indicate either permission or ability, while can was restricted to ability. Over time, may‘s domain has receded, and can‘s has expanded. In modern usage, can has taken on permission senses as well as its existing ability senses. May, on the other hand, has become largely restricted to the permission sense, although there are some “possibility”-type usages that still touch on ability, especially when speaking of the future:

The can expansion is a bit recent in historical terms, but that still means it’s been acceptable for over a hundred years — judging by the Tennyson citation — and commonplace for the last fifty or so. The recency explains the lingering resentment at permissive can, but it doesn’t justify it. Permissive can is here to stay, and there’s no reason to oppose it.**

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*: Not to telegraph my argument, but even here I find Mom said I can count to sound more like a statement of permission than ability.

**: I have some thoughts on whether it’s really even possible to draw a clear line between permission and ability — in essence addressing the question of whether the smearing together of can and may is an accident or inevitability. I’ll try to put them together at some point & link to them, but given my history of failing to follow through with follow-up posts, I’m not going to leave it as only a possibility, not a promise.

About The Blog

A lot of people make claims about what "good English" is. Much of what they say is flim-flam, and this blog aims to set the record straight. Its goal is to explain the motivations behind the real grammar of English and to debunk ill-founded claims about what is grammatical and what isn't. Somehow, this was enough to garner a favorable mention in the Wall Street Journal.

About Me

I'm Gabe Doyle, currently a postdoctoral scholar in the Language and Cognition Lab at Stanford University. Before that, I got a doctorate in linguistics from UC San Diego and a bachelor's in math from Princeton.

In my research, I look at how humans manage one of their greatest learning achievements: the acquisition of language. I build computational models of how people can learn language with cognitively-general processes and as few presuppositions as possible. Currently, I'm working on models for acquiring phonology and other constraint-based aspects of cognition.

I also examine how we can use large electronic resources, such as Twitter, to learn about how we speak to each other. Some of my recent work uses Twitter to map dialect regions in the United States.

25 comments

One of these days I want to write about the willful flouting of pragmatics encapsulated in responses like “I don’t know, can you?”

The etymology shows just how much can and may have shifted around in the past 1500 years. Can comes from the same root as know and originally meant knowing how to do something, May is related to the noun might and meant being physically able to do something.

And I think, as you suggest in your second note, that it really is difficult to disentangle the notions of permission and ability. I may be able to do something in the abstract, but I can’t really do it if my teacher won’t let me.

Most if not all the English modal auxiliaries are ambiguous (and that includes may): He may take the money – He’s likely to? Or he has permission to? You must love your father – A command? Or a deduction? He would say that – he used to? Or it’s the sort of thing he does? And so on. Why should “can” be so artificially restricted?

This distinction between “deontic” (permission) and “epistemic” (possibility) modalities is one that’s been discussed a lot in the formal semantics literature (e.g. Angelika Kratzer’s early work on modals). Across the world’s languages they’re actually frequently expressed using the same word, so I think this distinction people try to make between “can” and “may” is mostly fake. Less common (those claimed to exist in St’át’imcets, see Rullman/Matthewson/Davis 2008) is not having a distinction between “may” and “must”! So, English isn’t so crazy…

My grade school teachers’ insistence on this distinction did serve one very useful purpose for me when I was growing up. It allowed me, at a very early age, to realize that many authority figured have no idea what they’re talking about.

In my youth in Chicago, in the late ’40s, early ’50s we were commonly upbraided by our parents and teachers for saying “Can I … ?” when, we were told, we meant “May I … ?” In actual usage, however, these same parents and teachers would use “can” for permission. The only time I ever heard “may” used this way was in the name of a game we played, “Mother may I?”

dcreag gets at what the can/may issue is really about. It’s politeness, not grammar. To ask whether you may is deferential to adults while asking whether you can is appropriate for speaking to equals or subordinates.
The same thing happens with “I’m good” which can’t possibly be ungrammatical, but is sometimes considered too casual in response to “How are you?”

It seems to me you’re all forgetting courtesy and respect. I agree that sarcasm is not a good teaching method, but not that we can each use language according to our own lack of civility and expect to be admired for it.

Hello Margaret.
Courtesy and respect are one thing; grammaticality is another. It is polite to say, “Would you lend me twenty dollars?” It is informal and possibly impolite to say, “Give me twenty bucks.” Both are grammatical.
I think that’s the point of the can/may discussion.
Motivated Grammar is in favor of courtesy and respect, as far as I can tell.

“Youth clubs may be found…….” could infer that if you search for them there is a possibility of finding them. The same can be said of the second example. If we were to substitute Can for May as in “Youth clubs CAN be found……” we eliminate any ambiguity. It declares that you WILL find them.
Unlike the question “Can I go……,”, the CAN expressed here does not question the ability to do something,